Jack-up dredge

ABSTRACT

A dredge having a hull connected to a mobile platform by vertically extendable and retractable legs so that the mobile platform can be lowered to engage and move over the bottom of a body of water, and further so that the hull can be jacked-up above the surface of the water after the platform has engaged the bottom. Mounted upon the platform for operative engagement with the bottom is the dredging tool, such as a rotary cutter head, which may be mounted on the outer extremity of a ladder swingably mounted at its inner end to the platform. The hull is adapted to be propelled on the surface of the water when the platform is retracted, and is also adapted to support personnel and the controls for the operation of the dredge. A separate propulsion means is provided for moving the platform along the bottom.

[451 Sept. 4,1973

[ JACK-UP DREDGE [76] Inventor: Neil H. Cargile, Jr., 0/0 AmericanMarine & Machinery Co., P.O. Box 1067, Nashville, Tenn. 37202 [22]Filed: June 23, 1971 [21] Appl. No.: 155,934

[52] US. Cl... 37/67, 37/56, 61/465 2,938,353 5/1960 Vorenkamp 61/465813,935 2/1906 Avery, Jr. 37/56 3,495,409 2/1970 Riedemann 37/67 UX3,005,273 10/1961 Milne 37/73 X 3,001,370 9/1961 Templeton 61/4652,895,301 7/1959 Casagrande et a1. 61/46.5

FOREIGN PATENTS OR APPLICATIONS Germany 37/67 Primary Examiner-Robert E.Pulfrey Assistant Examiner'-C1ifford D. Crowder Azt0rneyHarrington A.Lackey [57] ABSTRACT A dredge having a hull connected to a mobileplatform by vertically extendable and retractable legs so that themobile platform can be lowered to engage and move over the bottom of abody of water, and further so that the hull can be jacked-up above thesurface of the water after the platform has engaged the bottom. Mountedupon the platform for operative engagement with the bottom is thedredging tool, such as a rotary cutter head, which may be mounted on theouter extremity of a ladder swingably mounted at its inner end to theplatform. The hull is adapted to be propelled on the surface of thewater when the platform is retracted, and is also adapted to supportpersonnel and the controls for the operation of the dredge. A separatepropulsion means is provided for moving the platform along the bottom.

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ATTORNEY JACK-UP DREDGE BACKGROUND OF THE INVENTION This inventionrelates to a hydraulic dredge, and more particularly to a hydraulicdredge having a mobile, jack-up platform.

Conventional hydraulic dredges include an elongated hull to the frontend of which is swingably mounted about horizontal and vertical axes aladder supporting a rotary cutter head. A suction pump is mounted on thehull and connected by a suction pipe to the cutter head for removing thespoil. Vertically reciprocable spuds are supported on the hull to anchorthe bull to the bottom, and also to provide a pivot post for swingingthe hull during the dredging operation. Spuds are also employed inconventional dredges for advancing the hull as the cutter head sweepsprogressively from one cut to the next.

Also known in the art are floating platforms or hulls provided with jacklegs to permit the hull to be jacked above the surface of the water.

SUMMARY OF THE INVENTION The hydraulic jack-up dredge made in accordancewith this invention includes a hull having means for propelling the hullupon the surface of a body of water. The hull carries, for verticalreciprocal movement, jack-up legs fixed to a submerged mobile platform.The legs may be driven up to retract the platform to a position beneathand proximate to the dredge hull, or they may be driven down until themobile platform engages the bottom of the body of water. Continueddownward driving of the jack-up legs causes the hull to be elevateduntil it is suspended above the surface of the water, and preferablyabove the waves.

Mounted on the front end of the platform is a ladder supporting adredging tool. The ladder is mounted upon the platform for vertical andhorizontal swinging movement. The cutter head is connected through asuction pipe to a suction pump, preferably mounted upon the platform,and to which is connected a discharge pipe. Motor means are provided,also preferably on the platform, for driving bottom-engaging wheelssupported on the platform.

Thus, with the platform in retracted position, the hull may be propelledto any desired location in a relatively shallow body of water fordredging, the legs extended until the platform wheels engage the bottom,and further extended until the hull is jacked up above the watersurface. The rotary cutter head is then driven, and the ladder is swungfrom side to side for dredging the bottom of the body of water. Thecutter head is advanced by driving the wheels to move the platform forward, while the hull functions as a control and operations platform forthe dredge personnel.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation of thejack-up dredge, made in accordance with this invention, in its operativedredging position with the legs extended and the hull jacked above thewater line, and with portions broken away to clarify the construction;and

FIG. 2 is a top plan view of the jack-up dredge disclosed in FIG. l,with portions broken away.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings inmore detail, the

5 jack-up dredge made in accordance with this invention includes anelongated hull 11 having a control cabin 12 mounted adjacent the stern.Twin-screw propellors 13 are mounted beneath the stem for propelling thehull 11 along the surface 14 of a body of water 15. Mounted adjacent thebow of the hull 11 is a diesel engine 17 for driving a hydraulic pump 18which supplies hydraulic fluid to the various hydlraulic drivesassociated with the dredge 10.

Received in recesses or wells 19in the hull 11 for ver' tical reciprocalmovement are a plurality of jack legs 20, four of which are disclosed inthe drawings. The legs 20 are of equal length substantially greater thanthe depth of the body of water 15 in which the dredge 10 is to beoperated. For example, if the dredge is to be operating in 20 feet ofwater, the legs 20 are typically about 30 feet long. To the bottom endsof the legs 20 is fixed a mobile platform 22 preferably of hollowconstruction to render the platform 22 buoyant. Mounted on both sides ofthe mobile platform 22 are sets of wheels 23 which are positively drivenby submersible hydraulic motors 24.

A winch 25 is mounted on the deck of the hull l l for raising andlowering each jack leg 20. Each winch 25 is driven by hydraulic motor26. One end of an upper cable 27 is fixed to the upper end of each leg20, while the opposite end of the upper cable 27 is wound in onedirection around winch 25. One end of a lower cable 28 is fixed to thebottom of the jack-up leg 20, while its opposite end is wound in theopposite direction around the winch 25. Each winch motor 26 is providedwith reversible fluid valve controls for reversing the direction ofrotation of the winch 25 in order to selectively lift or lower each leg20.

In this particular embodiment .of the jack-up dredge W, the front end ofthe platform 22 is located beneath the stern of the hull if, while therear end of the platform 22 is located beneath the bow of the hull l1.

Mounted on the front end of the platform 22 is a gimbel 30 including atongue 31 fixed to the front end of the platform 22 and a yoke frame 32mounted on pintle 33 to swing about a vertical axis relative to thetongue 31. Also, mounted on the front end of the platform 22 are a pairof hydraulic horizontal swing cylinders 34, the piston rods of which areattached to the opposite ends of the yoke frame 32. The cylinders 34 areadapted to be operated to react in opposite directions in order to swingthe frame 32 horizontally in one direction or the other about thevertical axis of the pintle 33.

The rear end of a ladder 35 is connected by hinge pins 36 to the yokeframe 32 for vertical pivotal movement about a horizontal axis. A pairof hydraulic veni- .cal swing cylinders 37 are pivotally mounted on theyoke frame 32 with their piston rods connected to the rear ends of theladder 35 in order to raise or lower the ladder 35 by reversiblycontrolling the hydraulic fluid to the cylinders 37.

Mounted on the front end of the ladder 35 is the dredging tool,specifically a rotary cutter head 40 driven by a submersible hydraulicmotor 41 also mounted adjacent the front end of the ladder 3S. Coupledto the cutter head All is a conventional suction pipe 42 carried by theladder 35 and running back to a suction pump 43 mounted upon theplatform 22. A suitable power drive, such as the hydraulic motor 44 isadapted to'drive the pump 43 in order to suck the discharge or spoilexcavated by the cutter head 40 through the pipe 42, pump 43 and outthrough the discharge pipe 45. Suitable extension pipes not shown, maybe connected to the discharge pipe 45 in order to discharge the spoil atany convenient location.

Hydraulic fluid from the pump 18 may be supplied to all of thehydraulically driven. devices, such as the wheel motors 24, pump motor44, horizontal swing cylinders 34, vertical swing cylinders 37, andcutter head motor 41, by the fluid lines 47, one of which is shown inFIG. 1. As disclosed in FIG. 1, the lines 47 are hinged by coupling 48so that they may be folded when the platform 22 is retracted toward thehull 11, and expanded, accordian-like, as the platform 22 is extendedfrom the hull 11.

In the operation of the dredge 10, the ladder 35 may be fixed in anyconvenient position relative to the platform 22, when the platform 22 isin its retracted, elevated position proximate to the bottom of the hull11. The hull 11 is then propelled along the water surface 14 by means ofthe twin-screw propellors 13 to the desired dredging location in ashallow area having a depth less than the height of the legs 20. Whenthe location is reached, the propulsion power for the hull 1 1 is turnedoff, and the winch motors 26 actuated to move the legs 20 down. Afterthe platform 22 has reached its lower limit with its wheels 23 engagingthe bottom 50, the winch motors 26 continue to be operated in the samedirection, to now cause the hull 11 to rise above the water line 14 to ajacked-up position, preferably above any waves which might buffet thehull 11. After the hull 11 has been jacked up to a safe operativeposition, such as that disclosed in FIG. 1, the winch motors 25 arestopped.

The operator of the dredge then actuates the controls in the controlcabin 12 to commence the dredging operation. The cutter head motor 41 isactuated to rotate the cutter head 40, and the ladder 35 is lowered bymeans of actuation of the vertical swing cylinders 37 until the cutterhead 40 engages the bottom 50 to commence its cut. The ladder 35 is thenswept horizontally from one side to the other by actuating thehorizontal swing cylinders 34. The pump motor 44 is started to drive thepump 43 to discharge the spoil excavated by the cutter head 40 throughthe suction pipe 42 and discharge pipe 45. As the first swath iscompleted by the cutter head 40, the motors 24 may be actuated to drivethe wheels 23 to move the platform 22 forward far enough for the cutterhead 40 to commence its next return swath.

After the dredging operation has been completed, the cutter head motor41, swing cylinders 34 and 37, pump motor 44 and wheel motors 24 arestopped. The winch motors 26 are then reversed to raise the legs 20 inthe leg wells 19 until the platform 22 is again in its retracted,elevated position adjacent to and beneath the bottom of the hull 11. Thetwin-screws 13 are then driven to propel the hull 1 1 back to shore, orto its next dredging operation.

The jack-up dredge 10 made in accordance with this invention isparticularly advantageous in dredging operations, such as beachreplenishment, shallow offshore dredging and channel clearing projects,particularly where adverse weather conditions exist. The jackup dredgel0 performs particularly well, in comparison with conventional dredges,in the cleaning of sand bars from inlets where vicious currents arepresent.

Where the body of water 15 is shallow enough, the ladder 35 could beoperatively connected to either end of the hull 11 by means such asgimbel 30. Pump 43 could also be located either on the hull 11 orplatform 22.

For some dredging operations, the hull 11 need not be floatable, butconstitute an upper platform to support personnel, equipment andcontrols. The sole propulsion would be the motivating drive for thelower platform 22, such as wheel motors 24. The propellers 13 could beeliminated. In this instance, the dredge would be driven into the water15 from the beach, and the upper platform 11 raised to the desiredelevation above the surface 14.

What is claimed is:

1. A dredge comprising:

a. an upper buoyant hull,

b. self-propulsion means on said hull for propelling said hull upon thesurface of a body of water,

c. a lower mobile platform having a front end and a rear end,

d. wheel means mounted on said lower platform for engaging the bottom ofa body of water and supporting said lower platform above said bottom,

e. hydraulic motor means on said platform for driving said wheels,

f. vertical legs having bottom ends fixed to said lower platform and aheight greater than the depth of the body of water in which said dredgeoperates,

g. means on said hull receiving said legs for vertical reciprocalmovement relative to said hull,

h. reversible hydraulic motor means on said hull operatively connectedto said legs for positively raising said legs to elevate said lowerplatform to a retracted position beneath and proximate to said hull, andto positively lower said legs to lower said platform to an extendedposition in which said wheels engage the bottom of the body of water andsaid hull is raised above the surface of the body of water,

i. a ladder having a front end and a rear end,

j. means mounting the rear end of said ladder on the front end of saidlower platform for vertical and horizontal swinging movement of saidladder, relative to said lower platform,

k. hydraulic swing motor means on said lower platform for positivelyswinging said ladder about a horizontal axis and for positively swingingsaid ladder about a vertical axis,

1. a rotary cutter head mounted on the front end of said ladder,

m. a hydraulic motor on the front end of said ladder drivingly connectedto said rotary cutter head,

n. a suction pipe operatively connected to said cutter head,

0. a suction pump mounted on said lower platform and operatively coupledto said suction pipe for conveying and discharging the spoil from saidcutter head,

p. hydraulic motor means on said lower platform for driving said suctionpump,

q. a hydraulic pump mounted on said hull,

ing a collapsible-expansible hydraulic line connecting said hydraulicpump to all said hydraulic motors on said lower platform and saidladder.

=0 *3 il t

1. A dredge comprising: a. an upper buoyant hull, b. self-propulsionmeans on said hull for propelling said hull upon the surface of a bodyof water, c. a lower mobile platform having a front end and a rear end,d. wheel means mounted on said lower platform for engaging the bottom ofa body of water and supporting said lower platform above said bottom, e.hydraulic motor means on said platform for driving said wheels, f.vertical legs having bottom ends fixed to said lower platform and aheight greater than the depth of the body of water in which said dredgeoperates, g. means on said hull receiving said legs for verticalreciprocal movement relative to said hull, h. reversible hydraulic motormeans on said hull operatively connected to said legs for positivelyraising said legs to elevate said lower platform to a retracted positionbeneath and proximate to said hull, and to positively lower said legs tolower said platform to an extended position in which said wheels engagethe bottom of the body of water and said hull is raised above thesurface of the body of water, i. a ladder having a front end and a rearend, j. means mounting the rear end of said ladder on the front end ofsaid lower platform for vertical and horizontal swinging movement ofsaid ladder, relative to said lower platform, k. hydraulic swing motormeans on said lower platform for positively swinging said ladder about ahorizontal axis and for positively swinging said ladder about a verticalaxis, l. a rotary cutter head mounted on the front end of said ladder,m. a hydraulic motor on the front end of said ladder drivingly connectedto said rotary cutter head, n. a suction pipe operatively connected tosaid cutter head, o. a suction pump mounted on said lower platform andoperatively coupled to said suction pipe for conveying and dischargingthe spoil from said cutter head, p. hydraulic motor means on said lowerplatform for driving said suction pump, q. a hydraulic pump mounted onsaid hull, r. drive means on said hull operatively connected to saidhydraulic pump for driving said pump, and s. a hydraulic circuitoperatively connecting said hydraulic pump to all said hydraulic motors,including a collapsibleexpansible hydraulic line connecting saidhydraulic pump to all said hydraulic motors on said lower platform andsaid ladder.